Steam generating system



July 12, 1938. A. CLARKSON STEAMTGENERATING SYSTEM Filed June 21, 1957 3 Sheets-Sheet l P. m J h 14/201 [Ya/ km 3 WW if flirts-$15.

July 12, 1938.

A. CLARKSON STEAM'. GENERATING SYSTEM 3 Sheets-Sheet 2 Filed June 21, 1937 Patented July 12, 1938 )UNITED STATES PATENT OFFICE STEAM GENERATING SYSTEM Aiick Clarkson, Elmluu'st, Ill. Application June 21, 1937, Serial No. 149,465

8 Claims. (Cl. 122-448) This invention relates to certain new and useful improvements in a steam generating system, and more particularly to improved means for automatically controlling the relative proportions of fuel and feed water as supplied to such a steam generating system. This application is a continuat-ion in part of the copending application of Alick Clarkson, Serial No. 99,736, filed Septem-- ber, 8, 1936.

The generator used in this system is of the forced circulation type in which a definite amount of excess water is circulated over and above that which is evaporated, the fluids from the generator being discharged into a separator operating preferably on the centrifugal principle, in which the excess water is separated from the steam. This excess water at hightemperature and pressure is caused by means of a heat exchanger to give up its heat tothe incoming feed water before such feed water is delivered to the generator. Thermostatic means-influenced by the temperature of this feed water is utilized to control the supply of fuel to the generator-heater thereby controlling the proportion of excess water circulated through the system. Means are also provided whereby the failure of the feedwater supply will automatically cut off the supply of fuel to the heater.

The principal object of the invention is to provide an improved steam generating system of the type briefly described hereinabove and disclosed more in detail in the specification which follows.

Another object is to provide an improved means for automatically controlling a steam generating system of the forced circulation type whereby there will always be an excess of water circulated through the generator.

Another object is to provide improved me for controlling the supply of fuel to the heater of a steam generating system of the type hereinabove set forth.

Another object is to provide improved mean of controlling the relative proportions of fuel and feed water delivered to the generator.

Another object is to provide an improved apparatus for separating the excess water from the steam.

Other objects and advantages of this invention will be more apparent from the following detailed description ofone approved form of apparatus constructed and operating according to the principles of this invention.

In the accompanying drawings:

Fig. 1 is a diagrammatic plan view of the assembled apparatus.

Fig. 2 is a partial elevation and partial vertical section, on a larger scale. of a portion of the mechanism at-the right hand side of Fig. 1.

Fig. 3 is a vertical central section through the improved separator. 5

Fig. 4 is a detail horizontal section taken substantially on the line 4-4 of Fig. 3.

Briefly described the system comprises the steam generator A provided with a burner B, the apparatus C for separating the steam and ex- 10 cess water, the fuel pump D, the air pump E, the feed water pump F, the heat exchanger G, the thermostatic mechanism H, which functions in response to temperature changes of the feed water as heated by exchanger G to actuate a portion of the valve mechanism J which controls the flow of fuel to burner B, and a shut-off mechanism K for stopping the flow of fuel tothe burner in case the pressure in the feed water supply line is reduced below a predetermined minimum.

The generator A is preferably of the forced circulation type through which feed water is forced under pressure, a portion of the water being evaporated into steam and a fluid mixture consisting of steam and excess water being dis- 2." charged into separator C. A preferred form of generator A is disclosed more in detail and claimed in the parent application Serial No.

. 99,736, hereinabove referred to. It is sumcient for present purposes to state that this generator consists of a plurality of vertically extending pipe coils or modified helices l, 2, 3, i, 5 and ii. The feed water is supplied through fitting I and inlet pipe 8 to the lower end of the outer coil i, and from the upper end of coil lthrough pipe 9 to the upper end of the next inner coil 2, and so on throughout the series. The mixture of steam and water is discharged from inner coil 6 through outlet pipe ll), fitting II and pipe iii to the separator C. The individual turns or loops of adjacent coils are preferably staggered with relation to one another so that the hot products of combustion from burner B which are introduced inside the stack or bank of coils and which flow outwardly between the several coils will engage a maximum surface area of the coils and thus transfer a maximum of heat to the fluids therein. a

The separator 0 comprises an outer casing consisting of outer shell l3, top member HI, and bottom member l5, which encloses the inner fluidholding assembly with interposed insulating spaces, such as indicated at 16. The inner assembly comprises an upper structure I! formed.

with a depending circular flange l8 having, prefring 22 and passes as a film down the inner face of this ring and shell 24. The out-turned lip |3 tendsto keep the water against the outer wall of this chamber. constricted annular opening 21 between lip i3 and shell 24 passes upwardly thrpugh member i1 and out of the separator through pipe 23 which may be provided with a pressure reducing valve'23 (see Fig. 1).

Positioned below the baiile structure I3 is a' hollow cone frustum 33 having an opening 3| in its upper end which is partially enclosed by a conical cap member 32 supported from cone 33 by the interposed spacers 33. The cone 33 is provided with an outer cylindrical flange 34, of smaller diameter than the inner diameter of shell 24, which flange is secured to the shell at 33 through interposed spacers 33.' This leaves a passage 31 between flange 34 and casing 24 through which the water flows into the lower portion of the separator. Inner casing 24 is connected at its lower end with the lower conical hopper member 33 oriflced at 33 for discharge through a blow-ofl. valve 43. The hopper member is also provided with a second outlet passage 4| for discharge of water into the pipe 42 leading to the heat exchanger G (see Fig. 1). The valve 43 cooperating with valve seat 44 and guided in fitting 43 controls the discharge of water through outlet passage 4|. when valve 43 is lifted from its seat, water collected in the lower portion of the separator flows out through strainer 43 and ports 41 formed in fltting 43 and thence into and through the discharge passage 4|. Movable valve member 43 is connected by link 43 with one end of a lever 43 pivoted at 33, the opposite end of this lever being connected through link 3| with one end of a lever 32 pivoted at 33 and carrying float 34. When a sufllcient head of water has collected in the separator chamber, float 34 will be elevated, thus lifting valve 43 from its seat and permitting the discharge of water from the separator. As the water level in the separator falls, the valve 43 will be lowered toward its seat thus diminishing the volume of the water stream discharged from the separator. In this manner the size of the stream of excess water discharged from the sepa rator will be proportioned to the rate at which water accumulates in the separator, that is in proportion to the volume of excess water passing through the generator. The separator may be provided with a water-gauge indicated at M.

The heat exchanger G (Fig. 1) consists of a vessel 33 in which is positioned a coil 33 connected at one end to discharge pipe 42 leading from the separator and at the other end with a water discharge pipe 31 which may lead back to the water supply tank, or any other desired point of discharge.

The air pump E driven by motor 33 forces air through conduit 33 to the burner B and the combustion chamber within the generator. The fuel pump D, which may be driven by the same power means as pump E draws fuel (preferably oil) from the source of supply through pipe 33, and

The steam issuing out through the forces this fuel through pipe 3|, T-iitting 32. T- fltting 33, and pipe 34 to the burner B of the generator-heater. This burner B is of the type provided with a valve which opens only under a certain predetermined minimum fuel pressure. In other words, if the pressure under which the fuel is supplied falls below this minimum, the valve will close and cut off the supply of fuel to the heating apparatus.

The lower passage leading from fitting 32 discharges into a chamber 33 having an outlet normally closed by a valve 33 held against its seat by spring 31. When valve 33 is lifted from its seat (in the manner hereinafter described) the fuel can flow from chamber 33 through pipe 33 and fitting 33 and discharge pipe 13 back to the fuel tank or other source of supply. The pipe 1| leading from the other outlet of T-fltting 33 discharges into a chamber 12 formed in the casing 13 of valve assembly J. The two ports 14 and 13 lead from valve chamber 12 into valve chamber 13 from which fuel is discharged through pipe 11, fitting 33 and discharge pipe 13 back to the fuel tank. The discharge through port 13 is controlled by valve 13 carried by stem 13 threaded into thimble 33 of packing 3|, the stem 13 being manually operable by means of handle 32. The flow of fuel through the other port 14 is controlled by a valve 33 mounted on stem 34 proiecting upwardly through packing 34' in the upper end of casing 13. Spring 33 confined between a bracket 33 in valve casing 13 and a stop 31 on the stem 34 tends to lift valve 33 and increase the valve opening. Valve 33 is forced downwardly to close the valve opening against the resistance of spring 33, by the thermostatic assembly H, as hereinafter described.

It will be understood. that in normal operation the pump D forces fuel through the piping system under suflicient pressure to open the valve at the burner B and supply fuel to the heating apparatus. It also pumps an excess volume of fuel so that a limited amount may be by-passed through either port 14 or port 13, chamber,"

and discharge pipes 11 and 13, back to the source of supply. In normal operation the valve 33 will be seated and valves 13 and 33 will be partially closed. At any time the amount of fuel bypassed may be adjusted by manually operated valve 13. Under certain conditions, when valve 33 is partially open, a sufllcient pressure to supply fuel to the burner may be obtained by closing the valve 13. However, if both valves .13 and 33 are opened, the amount of by-passed fuel will be sufficient to lower the pressure and cut off the supply at burner B. Also, if valve 33 is lifted, the fuel will be by-passed through this valve opening and pipe 13 so as to shut off the flow of fuel to the burner B.

The feed water pump F receives water from a source of supply through pipe 33 and discharges this water through pipe 33 into chamber 33 of diaphragm casing 3| of the shut-off device K. The diaphragm 32 mounted in this casing carries the valve member 33 adapted to cooperate with valve seat 34 at the entrance to discharge passage 33. Valve member 33 is provided with the balancing ducts 33 and 31 communicating with chamber 33 below the diaphragm 32. When feed water under suflicient pressure is forced by pump F into the upper chamber 33, the diaphragm 33 will be deflected downwardly, as shown in the drawings, so as to open valve 33 and permit this water to flow out through passage 33 and outlet pipe 33. A valve stem I33 projects upwardly III from movable valve member 00, and a spring IN is confined between the upper portion of the valve casing and an abutment I02 connected with valve stem I00. When the pump pressure normally exerted on diaphragm I fails, spring IOI will lift the valve 93 so as to cut off the water supply to pipe 99. It will be understood that when valve 93 is closed, the lower pressure existing in the piping system beyond device K will be communicated through balancing ducts 90 and 91 to the space 98 below the diaphragm so that the higher pump pressure will be efiective to open the valve. When the pump is in operation, the valve- 93 will not be moved very far from its seat and the rush of water through the annular passage around this valve will prevent the higher pressure from being communicated to the lower chamber 98 so that the valve will remain in this partially open position, as long as the pump pressure is maintained.

When the pump F is stopped or the pump pressure fails, the valve 93 will be closed by spring mi, and the upper end of valve stem I00 will engage and lift valve 66 from its seat, thus bypassing the fuel supply and shutting off the bumer B. Thus the burner cannot operate unless feed water is being supplied under proper pressure.

The thermostatic regulator H comprises a pair of heat expansible tubes I03 and I04 mounted at their lower ends in a connecting manifold I05 which is supported on spacing posts I06 projecting upwardly from valve casing", the manifold being anchored to the casing by bolts I01. The upper ends of tubes I03 and I04 are connected into a fitting I08. Feed water supply pipe 09 communicates with the upper end of tube I03 through nipple I09 connected into fitting I08. The lower end of tube I03 connects through manifold I05 with the lower end of tube I 04, the upper end of which connects through fitting I08, nipple I I0, and pipe I I I with one end of the heatexchanger tank 55. The other end 01' this tank connects through pipe I I2 provided with restricting valve H3, and pipe Ill with the upper end of a third heat expansible tube H5. This tube H5 is supported'at its upper end by stem IIS projecting through fitting I00 and held by nuts III, a spring IIB being interposed between the head of tube H5 and fitting I00. This spring II8 may be compressed to permit unusual expansion of tube II! but ordinarily the upper end of tube II5 may be considered as fixed to and moving with the fitting I00. The lower end of expansible tube II5 connects through pipe IIS, fitting I20 and pipe I2I with the inlet fitting I of the generator coils. A restricted shunt pipe connection I22 leads from pipe II2 to fitting I20. With valve II3 wide open the greater portion of the flow of heated water from tank 55 will pass downwardly through tube 5, but as valve H3 is progressively closed a greater portion of the flow will be diverted through the restricted connection I22 to the generator.

A stem I23 projects downwardly from the lower free end of tube H5 to engage the upper end of valve stem 04.

It will now be evident that the expansion of tubes I03 and I04 will tend to lift stem I23 and permit valve 83 to open, whereas the expansion of tube II5 tends to close the valve 83.

As the feed water fiows through casing 55 of the heat exchanger G on its way to the generator, this water will be heated by heat transferred discharged from separator C. This will expand tube IIS and tend to close valve 83, thus increasing the supply of fuel to bm'ner B. The amount of heat transferred to the feed water in heat exchanger G will dependupon the amount and temperature of the excess water passing through the generator and separator. If the supply of water is insufficient so that no excess is discharged from the separator, the feed water will not be heated and thermostatic device H will act to permit valve 03 to open and thus cut down or shut off the supply of fuel to burner B, thus decreasing the temperature of the generator. In this manner, overheating of the generator so as to cause damage to the tubing in the absence of suiiicient water supply is prevented. The proportion of water converted into steam may be varied by proper adjustment of the thermostatic regulator. It will be noted that the heat transferred to the feed water in heat exchanger .G is dependent not only on the temperature of the water discharged from the separator but on the amount of such water. If there is insufficient feed water supplied to the generator, or if an excessive quantity of the water is converted into steam, the discharged water will be reduced to such a small stream thatthe heat imparted to the feed water will be insufilcient to close valve 03, even though this excess water is at a high temperature.

If the feed water initially supplied through pipe 99 is heated, this heat will expand the tubes I 03 am I04 thus lifting the tube 5 and partially counteracting the effect of the expansion of tube H5. In this way compensation is made for preheated water so that the final control of the fuel supply will depend on the amount or temperature of the excess water from the separator.

I claim:

' 1. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam, means for delivering feed water to the generator, a heater for the generator, a separator for'receiving the mixture of water and steam from the generator and separating the steam from the water, and means for increasing or decreasing the supply of fuel to the heater as the amount of water discharged from the separator increases or decreases.

2. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam} means for delivering feed water to the generator, a heater for the generator, a separator for re-- ceiving the mixture of water and steam from the generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water going to the generator are separately passed in heat exchange relation, and means for increasing or decreasing the supply of fuel to the heater as the amount of heat delivered by the discharged water to the feed water in the heat exchanger increases or decreases.

3. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam, means for delivering feed water to the generator, a heater for the generator, a separator for receiving the mixture of water and steam from the generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water to the generator are separately passed for heat exchange, and means for increasing or decreasing the supply of fuel to the heater as the temperature oi the feed water delivered to the generator increases or decreases.

4. In steam generating apparatus, the combination or a generator through which water is circulated and partially converted into steam, means for delivering feecbwater to the generator, a heater for the generator, a separator for receiving the mixture of water and steam from the generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water to the generator are generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water to the generator are separately passed for heat exchange, and means for diminishing the supply of fuel to the heater as the temperature of the feed water delivered from the heat exchanger falls.

6. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam,

I means for delivering feed water to the generator,

a heater for the' generator, a separator for receiving the mixture of water and steam from the generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water to the generator are separately passed for heat exchange, and thermostatically controlled means responsive to temperature changes oi. the feed water delivered from the heat exchanger for shutting oi! the supply of Iuel to the heater when the flow of water from the separator is stopped.

7. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam, means for delivering feed water to the generator, a heater for the generator, a separator for receiving the mixture of water and steam from the generator and separating the steam from the water, means tor discharging water from the separator, and'thermostatically controlled means responsive to an increase or decrease in the amount of heat delivered from the separator by the discharge water for increasing or decreasing the supply of fuel to the heater.

8. In steam generating apparatus, the combination of a generator through which water is circulated and partially converted into steam, means for delivering'teed water to the generator, a heater for the generator, a separator for receiving the mixture of water and steam from the generator and separating the steam from the water, means for discharging water from the separator, a heat exchanger through which this discharged water and the feed water to the generator are separately passed for heat exchange, and thermostatically controlled means responsive to temperature changes of the feed water as delivered both to and from the heat exchanger on its way to the generator for controlling the supply of fuel to the heater.

ALICK CLARKSON. 

